Determination of the Deformed Shape of a Masonry Wall Exposed to Fire Loading by a Homogenization Method

The present contribution shows how it is possible to determine the homogenized thermo-elastic characteristics of a natural stone masonry wall, taking into account the material properties of stone and mortar as functions of temperature increase, as well as the geometrical characteristics of their assembly. Joints are incorporated in the analysis through a numerical homogenization procedure. As a result, membrane and bending stiffness coefficients, as well as thermal-induced efforts, of an equivalent plate are obtained. Such homogenized thermomechanical characteristics make it possible to determine the deformed shape of the wall after a certain time of fire exposure. As an example, the calculation procedure is performed on a particular configuration of infinitely wide wall, illustrating the influence of the joints on its thermal deformed shape. To assess the practical validity of this homogenization-based calculation procedure, results of the numerical homogenized model (incorporating joints) are compared to those of a homogeneous model (without joints), and to available experimental results obtained on a 3 m-high, 3 m-wide wall exposed to fire loading.

A localization method for wireless capsule endoscopy using side wall cameras and IMU sensor

Localizing the endoscopy capsule inside gastrointestinal (GI) system provides key information which leads to GI abnormality tracking and precision medical delivery. In this paper, we have proposed a new method to localize the capsule inside human GI track. We propose to equip the capsule with four side wall cameras and an Inertial Measurement Unit (IMU), that consists of 9 Degree-Of-Freedom (DOF) including a gyroscope, an accelerometer and a magnetometer to monitor the capsule’s orientation and direction of travel. The low resolution mono-chromatic cameras, installed along the wide wall, are responsible to measure the actual capsule movement, not the involuntary motion of the small intestine. Finally, a fusion algorithm is used to combine all data to derive the traveled path and plot the trajectory. Compared to other methods, the presented system is resistive to surrounding conditions, such as GI nonhomogeneous structure and involuntary small bowel movements. In addition, it does not require external antenna or arrays. Therefore, GI tracking can be achieved without disturbing patients’ daily activities.

A Localization Method for Wireless Capsule Endoscopy Using Side Wall Cameras and IMU Sensor

Localizing the endoscopy capsule inside gastrointestinal (GI) system provides key information which leads to GI abnormality tracking and precision medical delivery. In this paper, we have proposed a new method to localize the capsule inside human GI track. We propose to equip the capsule with four side wall cameras and an Inertial Measurement Unit (IMU), that consists of 9 Degree-Of-Freedom (DOF) including a gyroscope, an accelerometer and a magnetometer to monitor the capsule’s orientation and direction of travel. The low resolution mono-chromatic cameras, installed along the wide wall, are responsible to measure the actual capsule movement, not the involuntary motion of the small intestine. Finally, a fusion algorithm is used to combine all data to derive the traveled path and plot the trajectory. Compared to other methods, the presented system is resistive to surrounding conditions, such as GI nonhomogeneous structure and involuntary small bowel movements. In addition, it does not require external antenna or arrays. Therefore, GI tracking can be achieved without disturbing patients’ daily activities.

Оn the experiment validity of the continuous medium motion detection by the waveguide method

Present work is devoted to the problem of validity increasing of an experiment to detect the motion of a continuous medium by the waveguide method. The study attempts to optimize the experiment to find the optimal scheme for its installation. The target effect, the magnitude of which should be maximum, is the generalized reflection coefficient, which is influenced by both the Fresnel electromagnetic drag coefficient and the polarization plane rotation due to motion of the medium. The main optimization task is to determine the output parameters for the experiment for stable and reliable motion detection of a continuous medium in a waveguide. In this work, a heuristic analysis algorithm is used. Optimization factors: frequency of the signal at microwave, physical dimensions of objects, shape of the waveguide cross-section, linear velocity of the medium. ECAD PathWave EM Design (EMPro) 2021 was used to the experiment designing stages. Distilled water is the moving medium, which is not subject to optimization. The motion of a continuous medium is considered through its refined refractive index. The maximum magnitude of the target effect is observed for the topology with a rectangular waveguide and with a tube oriented along a wide wall at f = [9.3 ÷ 9.5] GHz. These values coincide with a good degree of accuracy with the already conducted experiments.

A SIW Horn Antenna without Broad Wall Loaded with Trapezoidal Air Slot

In this paper, a SIW horn antenna without broad wall loaded with trapezoidal air slot is proposed, processed, and tested. Based on the SIW horn antenna, this antenna strips off the wide wall at the horn diameter, introduces surface waves on the surface of the dielectric substrate, and improves the impedance matching between the antenna and free space. Further, trapezoidal air slots are loaded on the exposed dielectric substrate, gradually changes the dielectric constant of the dielectric substrate, so that the dielectric constant of the dielectric substrate can get closer to which of air, and the working bandwidth can be further expanded. The actual measurement results show that the working bandwidth of the antenna is 15.2-38GHz, the relative bandwidth reaches to 85.7%, and the maximum gain in the band is 9.1dBi.

Дефектная мода в СВЧ волноводных брэгговских структурах с металлическими штырями

A waveguide Bragg structure containing equidistant cylindrical pins that are galvanically coupled to a wide wall of the waveguide is used to implement frequency response functions characterized by the presence of a band gap. Characteristics of a defect mode of the microwave photonic crystal with a pin element as a defect with an n – i – p – i – n structure with controlled conductivity placed in the capacitive gap are experimentally studied and calculated. Controlled reflectance of a microwave signal with a dynamic range of greater than 50 dB is obtained at the frequency of the defect mode.

SEISMIC RESISTANCE INVESTIGATION OF A LARGE-PANEL BUILDING WITH SUPER-WIDE WALL SPACING

В работе рассмотрена проблема сейсмического прогноза и его эффективности. Проведен анализ ситуации при реализации среднесрочного прогноза разрушительного Тбилисского землетрясения 25 апреля 2002 года в Грузии. Рассмотрены инженерно-геологические, геоморфологические и гидрогеологические условия г. Тбилиси. Показаны изосейсты 5‑ти бального форшока и 7‑ми бального основного толчка. В данной статье рассматриваются записи ряда разрушительных землетрясений, очаг которых находился вблизи урбанизированной территории. Проведен анализ инструментальных записей. Показано, что нахождение урбанизированной территории в ближней зоне источника обуславливает наличие высокочастотной вертикальной составляющей, предваряющей основные колебания. Хорошо известно, что поглощение сейсмических волн прямо пропорционально частоте колебаний, что предполагает быстрое затухание высокочастотной составляющей сигнала. При этом, за редким исключением, большинство записей производится станциями, достаточно удаленными от места событий. Традиционное использование инерционных сейсмоприемников при этом исключает регистрацию указанных высокочастотных сигналов. Исходя из того обстоятельства, что землетрясения расположены непосредственно под территорией г. Тбилиси использование соответствующих записей должно позволить получать реакции зданий и сооружений на подобные воздействия максимально приближенными к реальным условиям. В этой связи исследована эффективность применения в жилых зданиях конструктивной схемы с супершироким шагом на примере 5‑этажного крупнопанельного дома. Был произведен динамический расчет методом конечных элементов The problem of earthquake prediction and its effectiveness is discussed. The analysis of the situation with the implementation of the medium-term forecast of devastating earthquake April 25, 2002, Tbilisi, Georgia was held. Engineering-geological, geomorphological and hydrogeological conditions of Tbilisi are reviewed. 5‑point forshock and 7‑point main shock isoseists are shown. This article discusses a number of devastating earthquakes records, which source was close to the urbanized territory. The analysis of instrumental records was held. It is shown that the near-source zone urbanized territory determines the availability of high-frequency vertical component, anticipating major fluctuations. It is well known that absorption of seismic waves is directly proportional to the frequency of the oscillations, which involves rapid attenuation of signal high-frequency component. Thus, with few exceptions, most of the records produced by stations, quite remote from the scene. Traditional use of inertial seismic detectors excludes the registration of these high frequency signals. Earthquakes are located directly beneath the territory of Tbilisi so the use of appropriate records should enable to receive buildings and structures reactions to such impact closest to real conditions. In this context, we investigated the efficacy of residential design concept with super-wide wall spacing on the example of 5‑storeyed large-panel building. Dynamic calculation using finite element was produced.

Heat Transfer and Pressure Loss Measurements in a Turbulated High Aspect Ratio Channel With Large Reynolds Number Flows

Experiments to investigate heat transfer and pressure loss are performed in a rectangular channel with an aspect ratio of 6 at very high Reynolds numbers under compressible flow conditions. Reynolds numbers up to 1.3 × 106 are tested. The presence of a turbulated wall and the resultant heat transfer enhancement against a smooth surface is investigated. Three dimpled configurations including spherical and cylindrical dimples are studied on one wide wall of the channel. The presence of discrete ribs on the same wide wall is also investigated. A steady state heat transfer measurement method is used to obtain the heat transfer coefficients while pressure taps located at several streamwise locations in the channel walls are used to record the static pressures on the surface. Experiments are performed for a wide range of Reynolds numbers from the incompressible (Re = 100,000–500,000; Mach = 0.04–0.19) to compressible flow regimes (Re = 900,000–1,300,000, Mach = 0.35–0.5). Results for low Reynolds numbers are compared to existing heat transfer data available in open literature for similar configurations. Heat transfer enhancement is found to decrease at high Re with the discrete rib configurations providing the best enhancement but highest pressure losses. However, the small spherical dimples show the best thermal performance. Results can be used for the combustor liner back side cooling at high Reynolds number flow conditions. Local measurements using the steady state, hue-detection based liquid crystal technique are also performed in the fully developed region for case 1 with large spherical dimples. Good comparison is obtained between averaged local heat transfer coefficient measurements and from thermocouple measurements.